The focus of the latest race row to engulf the White House has swung to the rightwing blogger who instigated the furore by posting an edited version of a speech made by one of the federal government's senior black officials.

Andrew Breitbart found himself at the centre of the storm after he posted parts of a speech by Shirley Sherrod, the head of rural development for the agriculture department in Georgia, on the internet. The clips were edited to give the impression that Sherrod had been making discriminatory comments against white farmers, when in fact she had been recalling a parable designed to show that poor people should be treated equally whatever their race.

Sherrod was fired within hours of Breitbart posting the footage on Monday but later her full speech from March was aired, clearing her of any hint of racism. That led to apologies to her from the White House, the agriculture secretary, Tom Vilsack, and media pundits who had swallowed Breitbart's version without checking its veracity.

Today Sherrod conducted a round of television interviews in which she threatened to sue Breitbart for damage to her reputation. She told CNN's morning news magazine that she would like to "get back" at the blogger and see his website shut down.

"That would be a great thing. He's doing more to divide us," she said.

She told NBC News that Breitbart "knew his actions would take Shirley Sherrod down. It would be hard for me to forgive him at this point."

Breitbart posted the misleading video on his site BigGovernment.com, which he bills as a rightwing version of the Huffington Post, the now liberal news aggregator he used to work on. So far he has been one of the few parties in the saga not to offer an apology to Sherrod, though he has said he felt sorry for her.

Breitbart's website insisted he had done no editing himself of the speech, running footage he had been handed by an unidentified source in its entirety. "We did not edit, much less misleadingly edit, any of Ms Sherrod's remarks. We posted two excerpts from her speech, representing the sum total of the video we had. We didn't cut anything out of her speech," a post on the site said.

While much of the spotlight now plays on Breitbart amid suggestions that he victimised Sherrod in an attempt to discredit the NAACP, the largest civil rights group in America which hosted her speech, questions continue to be asked about why the Obama administration sacked her so quickly on the word of an avowedly partisan blogger. Sherrod insisted her dismissal was carried out with the full knowledge of the White House.

She told NBC News she continued to admire President Barack Obama, but added: "I'd like to talk to him a little bit about the experiences of people like me. People who live out there in rural America. People who live in the south. I know he does not have that kind of experience. Let me help him a little bit with how we think, how we live and the things that are happening."